The present invention relates to an imaging device for modulating the optical transfer function of the optical image by way of an optical phase filter to increase the depth of focus and to obtain a sharp image by removing the modulation component through image processing.
A known background technology for the technical field is disclosed for example in U.S. Pat. No. 5,748,371. The U.S. Pat. No. 5,748,371 discloses a technology in which an optical mask that modulates the optical phase is mounted in the optical system and is designed to make the OTF (Optical Transfer Function) essentially constant within a certain distance range from the focused focal point position in order to increase the depth of field, and further in which signal processing is performed on the modulated intermediate image subjected to modulation from the OTF by the optical mask to remove the modulation effects caused by the optical mask, and in this way increase the depth of field.